Electric crossbar switches

ABSTRACT

A crossbar switch in which an array of contact sets is formed by a cross-wire matrix. The contact sets are operated by movement of respective &#39;&#39;interposer members&#39;&#39; into the plane of the array. The interposer members are operated selectively by coordinate crossbar systems one of which moves a row of interposer members into driving positions underneath the respective contact sets and the other of which, crossing the first, drives the selected one of the positioned interposer members into operative engagement with the selected contact set. The interposer members are carried by, and magnetically located on, the bars of the first coordinate system so that operation of a bar of the first system does not disturb a previous connection made by the same bar, the magnetic coupling accommodating the relative movement of the interposer members.

[5 6] References Cited UNITED STATES PATENTS 3,478,285 l 1/1969 Haines et al. 335/112 Primary Examiner-Harold Broome Attvrney-Kirschstein, Kirschstein, Ottinger and Frank lnventor Donald Edward Rowley Coventry, England Appl. No. 874,791

Filed Nov. 7, 1969 Patented May 18, 1971 Assignee The General Electric and English Electric Companies Limited London, England United States Patent array of contact -wire matrix. The contact sets are of respective interposer members rray. The interposer members are coordinate crossbar systems one of nterposer members into driving posispective contact sets and the other of drives the selected one of the posimbers into operative engagement with The interposer members are carried y located on, the bars of the first coort operation of a bar of the first system does ous connection made by the same bar, the dating the relative movement of n a h .m h w .m h m 0 m m S a 0t .1 t m mm a me mm S mt e t a m fa mm m m m CYVOVO r C V bo m wnfi m A mflcaa m spp u ym mmdm mbmaw cm m flmmmmm o d n C wmwmn mdwmflw .mm mh h d m m s r I m mS dm B tmhm nm e nnmae Mmmnmowfiwnmbdnmm 6 H7 1 5 57 H O 0 mm m mt .3 S m m M m m1 "1|. C m m T m m0 m u "l. 0 8 u u o n "9 coi u 0 6m :l u 1 9--8 BF a 1T6 800 n "O0 98/ s u "0 8 0 m 1 Ra mm 0 3 C "2m NGS D hr 7 mmqm 5 mm V. Tm LL o .m m n m to s sm Di E6 UIF ll] lzl] 23 4 2 0 333 5 555 .lll. ll

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NVENTQK lwno map E m ELECTRIC CROSSBAR SWITCHES 1 This invention relates to electric switches and particularly to coordinate switches, such as that known as a crossbar switch, for use in telephone switching systems.

As used in this specification, a coordinate switch means one having a plurality of contact sets which are grouped in two ways such that each contact set occurs in one group of the first grouping and in one group of the second grouping, each contact set being uniquely defined by two such groups and operated by selective operation of each of two coordinate systems of operating members which systems respectively select the two groups.

US. Pat. application Ser. No. 692,074 filed Dec. 20, I967, now U.S. Letters Pat. No. 3,478,285 granted Nov. 1 I, I969 is directed to a coordinate switch comprising a matrix of contact sets arranged to be operable selectively by two sets of coordinate means, each contact set being operated by an associated interposer member which is arranged to be movable parallel to the plane of the matrix by one set of said coordinate means and, independently, transverse to the plane of the matrix by the other set of said coordinate means, the interposer member having two positions in which the associated contact set is, respectively, unoperated and operated, and that position of an interposer member in which the associated contact set is operated being attainable only by a combination of said parallel and transverse movements.

According to the present invention, in coordinate switch as hereinbefore defined, and including an interposer member in respect of each contact set, each interposer member being movable in a first direction by selective operation of one of the two coordinate systems of operating members and in a second direction by selective operation of the other coordinate system of operating members, the combined movements being arranged to cause operation of the respective contact set. said one coordinate system of operating members is coupled to the interposer members magnetically.

The operating members of said first coordinate system may be longitudinal members aligned with said first direction. said second direction being transverse to the longitudinal members.

Each said longitudinal member may have a series of locally magnetized portions. Alternatively, each said longitudinal member may comprise a series of magnetized members supported by nonferromagnetic material.

Each said longitudinal member may comprise a series of low reluctance portions of ferromagnetic material, each interposer member then being ferromagnetic and magnetized.

A coordinate switch in accordance with the invention will now be described by way of example, with reference to the accompanying drawings, of which:

FIG. 1 is a diagrammatic perspective view of the switch;

FIG. 2 is a plan view of the switch;

FIG. 3 is a fragmentary sectional rear elevation of the switch showing one contact crosspoint;

FIG. 4 is a fragmentary plan view of the lower part of the switch shown in FIG. 2, broken away to show the operating mechanism;

FIG. 5 is a right-hand end view of the switch shown in FIG. 2, with part broken away;

FIG. 6 is a perspective view of a detail of the switch, a select bar and interposer members; and

FIG. 7 is a plan view of the select bar of FIG. 6.

The switch illustrated is a modification of the switch described in the above patent which gives further information on details of the construction and operation of the switch not directly relevant to the present invention. In order, however, to assist cross reference, the same references have been used in the accompanying drawings as in the drawings of the above patent where there is correspondence.

The present switch comprises a matrix of contact sets and an operating mechanism which are shown in the upper and lower parts respectively of FIGS. 1 and 2. As shown in FIG. 1, the matrix of contact sets is in fact a conductor matrix comprising l2 tiers of conductor wires which, in each tier, are arranged as rows and columns. There are basically I0 row wires land 10 column wires 2 in each tier, with an additional three rows which will be called level-switching rows. The wire arrangement of the level-switching rows is modified from the basic arrangement-as will be explained. The 12 tiers are superimposed so that corresponding columns in the different tiers form a column plane and corresponding rows form row planes. The intersection of a row plane and a column plane provides a crosspoint contact set of l2 contact pairs, each such pair being formed by a row wire 1 and a column wire 2. The row wires in each tier are spaced apart slightly from the column wires so that normally there is no electrical contact between them.

In FIG. 1 the column wires 2 are shown, like the row wires 2, as single conductors for clarity. The column wires 2 are in fact doubled to provide security as shown in FIG. 3 which is a detail section of a particular contact pair.

Any of the IQ row wires 1 in a tier can be connected to any column wire in that tier by deflection of the row wire 1 at the appropriate crosspoint. However, the present switch is required to make multiple connections in unison for telephone purposes, and for this reason all 12 contact pairs of a crosspoint contact set operate in unison. In general only four of the 12 connections are sufiicient for a particular telephone call and its supervision, and the purpose of the three levelswitching rows mentioned above is to select one of the three groups, each group .of four contact pairs, that are provided by the 12 tiers, when all 12 contact pairs are operated.

Inlet connections to the switch are made to the various columns of the level-switching rows. In each column plane 12 inlet column conductors extend into the level-switching rows, four into the first row, four into the second row and four into the third row. The three groups are commoned at the inlet to the switch to provide a four-wire inlet for the particular column plane. Thus a total of 10 four-wire inlets are provided. The first level-switching row makes connection between the four inlet column wires in one of the three groups and the basic column wires 2 in the corresponding four tiers. The second level-switching row makes connection between the four inlet column wires in the second of the three groups and the basic column wires 2 in'the corresponding four tiers. The third level-switching row does correspondingly. Thus the fourwire input to a column plane is extended to a particular four of the basic 12 column wires. From these four column wires 2, connections are made to four of the 12 row wires 1 in a selected one of the basic l0 rows. A choice of 10 X three fourwire outlets is thus available to each four-wire inlet, the particular one of the three levels being selected by the choice of level-switching row.

To complete a four-wire path through the switch, therefore, two contact sets have to be operated in one column plane, one to select the level and one to select the outlet row.

Each contact set has a respective comb member 3, the 12 cantilever teeth 4 of which interleave the tiers so that the tip 13 of one tooth 4 is adjacent to each contact pair, as shown in FIG. 3. In FIG. 1 the combs 3 are shown below the whole conductor matrix, for clarity, but the teeth 4 are, as stated, in fact interleaved with the wires of the matrix.

A contact set is then operated by driving the comb 3 transverse to the tiers so that each tooth tip drives a row wire into contact with a column wire.

The mechanism for operating the contact sets selectively is basically similar to that described in the patent referred to above. A bridge magnet 166/183 in respect of each column of the conductor matrix operates an armature structure 172 which includes a bar, the bridge bar 176, extending the length of the column immediately beneath (in FIG. 1) the lower ends 127 of the combs 3 of the particular column. The armature structures 172 are pivoted on pivots 174 as shown in FIGS. 2 and 4 so that energization of a bridge magnet winding 183 causes an armature bar 168 to move towards the combs 3 of the particular column. The gap between the bridge bar 176 and thelower extremities of the combs 3 is, however, such that, in the absence of any intervening member, the movement of the bridge bar 176 is insufficient to reach the combs 3.

The above intervening member is provided by an interposer member 205 shown in FIGS. 1, 4 and 6, which may be contrasted with the interposer members described in the above application.

The interposer members 205 for a row of contact sets are carried by a select bar 208. The select bars together form one system of coordinate members, the above bridge bars 176 forming a second system and the two systems together effecting selection of a particular contact set.

The select bars 208 are mounted in guide blocks 187 and are driven longitudinally by select magnets 193. Each select bar 208 is made of a ferrite material and is magnetized in stripes transversely, as shown in FIG. 7, to provide a row of north poles along one edge and a row of south poles along the other. The pitch of the magnetized stripes is equal to the pitch of the columns of the conductor matrix.

Each interposer member 205 comprises a rectangular blockof ferromagnetic material having a hole' right through it to make the block a loose fit on the select bar 208. The interposer member normally rests in engagement with the select bar 208 in the position shown in FIG. 6. The longitudinal position of the interposer member is maintained by the magnetic coupling between the interposer member and its local magnetic stripe, this coupling being such as to return the interposer member after a small longitudinal displacement.

The normal position of a select bar 208 is such as to position the interposer members 205 carried by it just to the left, in

FIG. 4, of the respective gaps between the bridge bars 176 and the lower ends 127 of the combs 3. The dimensions of each interposer member 205 are such as to permit its interposition in the gap by longitudinal movement of the select bar 208 without obstruction by the comb extension 127 and the bridge bar 176. When so interposed, operation of a bridge magnet causes the associated bridge bar, 176 to engage the interposer member 205 and drive it into engagement with the comb extension 127. Movement of the comb 3 transverse to the conductor matrix then causes operation of the 12 contact pairs of the contact set.

Or operation of the bridge magnet 183 in the above circumstance, the interposer member 205 is trapped by friction between the bridge bar 176 and the comb extension 127. If the associated select-bar magnet 193 is then tripped, the select bar 208 will move back towards the left in FIG. 4 under the control of a return spring on the armature of the select magnet 193. However, the magnetic coupling between the trapper interposer member and the select bar allows relative movement between the two, so leaving the selected contact set operated and held on by the bridge magnet. Subsequent tripping of the bridge magnet releases the interposer member 205 which moves both downwards and to the left in FIG. 4 to regain its home position on its magnetic stripe.

' Transverse movement of the interposer member 205 on the select bar 208 when the bridge magnet is tripped, that is, the downward movement in FIG. 4 is achieved by differential magnetic paths for the stripe flux in the upper and lower limbs of the interposer member. As shown in FIG. 6, a slot is formed in the lower path to increase the lower path reluctance. Various other ways of achieving this return movement will present themselves. The interposer may be magnetically formed in other ways than with a slot. A leaf spring may be fitted to the select bar, incidentally assisting the longitudinal return movement.

It is necessary that the interposer member 205 does return downwardly (in FlG. 4) on release so that its longitudinal movement is not obstructed by the comb extension 127 on the next operation.

The magnetic coupling between each interposer member 205 and its local stripe on a select bar 208 allows a select bar to operate two or more contact sets in the same row without the second or later operation conflicting with the earlier operation. Once an interposer member 205 has been trapped in the operation of a particular contact set further operation of the same select bar will merely relieve and then reimpose the magnetic stress on the trapped interposer member without disturbing it.

ln effecting a four-wire path through the switch the operation is as follows. A select magnet 193 for a chosen levelswitching row is energized thus moving all the interposer members 205 of that row into their respective gaps. A select magnet 193 for the chosen outlet row of the l0 available is also energized, similarly moving all the interposer members 205 of that row into their respective gaps. The four-wire outlet path has thus been defined by level and row.

A chosen bridge magnet is then operated, so trapping those interposer members of the two selected rows'which fall in the column associated with the bridge magnet. Two contact sets are thus operated at the cross-points of the two selected rows and the column, and the path through the switch is completed. The two select magnets may then be released and the path remains for such time as the associated bridge magnet is held on.'

It may be desirable to provide positive limitations to the local movements of the interposer member 205 on their select bars 208 to ensure that an interposer member is not displaced beyond the influence of its own stripe. Pegs or notches in the bar, or any other such local obstruction would suffice.

The actual magnetic system may be varied in many ways from that disclosed above. The bar may be magnetized longitudinally to provide one pole at each home. position of the interposers. The bar could consist of nonferromagnetic material having small magnets built in periodically. Again, the interposer may be magnetized and the bar not. The interposer may be in the form of a two-part dumbbell mounted in a slot in the select bar. This would have the advantage of providing the positive limitation of the movement of the interposer. Many such variations all within the scope of the invention will suggest themselves.

Variations of the arrangement of coordinate members are possible. Thus, for example, the bars may be aligned with columns instead of rows, each bar carrying an interposer member for each of the l3 rows. Each interposer member may then be longitudinally trapped on its bar but transversely movable against a magnetic bias. A select magnet would then displace the interposer members of one row (all on different bars) transversely into a position in which longitudinal movement of a'chosen bar would operate a selected contact set by way of the displaced interposer member on that bar, so trapping the displaced interposer member and allowing the select magnet ,to be released.

lclaim:

l. A coordinate switch comprising a plurality of contact sets, an interposer member in respect of each contact set, each interposer member being mounted for movement in first and second directions, the combination of the movements causing operation of the associated contact set, and first and second coordinate systems of operating members, said first coordinate system being coupled to said interposer members to produce said movement in said first direction and said second coordinate system being coupled to said interposer members to produce said movement in said second direction, selective operation of the two coordinate systems producing operation of a single contact set, wherein the coupling between said first coordinate system and said interposer members is magnetic.

2. A coordinate switch according to claim 1 wherein the operating members of said first coordinate system are longitudinal members mounted in alignment with said first direction, each of said longitudinal members carrying a plurality of said interposer members.

3. A coordinate switch according to claim 2, wherein each said longitudinal member has a series of locally magnetized portions, each of said portions coupling with a respective interposer member.

4. A coordinate switch according to claim 2, wherein each said longitudinal member comprises a series of magnetized members supported by nonferromagnetic material.

said longitudinal member comprises a series of low-reluctance portions of ferromagnetic material and each said interposer member is ferromagnetic and magnetized. 

1. A coordinate switch comprising a plurality of contact sets, an interposer member in respect of each contact set, each interposer member being mounted for movement in first and second directions, the combination of the movements causing operation of the associated contact set, and first and second coordinate systems of operating members, said first coordinate system being coupled to said interposer members to produce said movement in said first direction and said second coordinate system being coupled to said interposer members to produce said movement in said second direction, selective operation of the two coordinate systems producing operation of a single contact set, wherein the coupling between said first coordinate system and said interposer members is magnetic.
 2. A coordinate switch according to claim 1 wherein the operating members of said first coordinate system are longitudinal members mounted in alignment with said first direction, each of said longitudinal members carrying a plurality of said interposer members.
 3. A coordinate switch according to claim 2, wherein each said longitudinal member has a series of locally magnetized portions, each of said portions coupling with a respective interposer member.
 4. A coordinate switch according to claim 2, wherein each said longitudinal member comprises a series of magnetized members supported by nonferromagnetic material.
 5. A coordinate switch according to claim 2 wherein each interposer member comprises a piece of nonmagnetized ferromagnetic material.
 6. A coordinate switch according to claim 2, wherein each said longitudinal member comprises a series of low-reluctance portions of ferromagnetic material and each said interposer member is ferromagnetic and magnetized. 